Lecture 3 - Non Regenerative Anaemia

Question 1

define NRA

Answer 1

anaemia without concurrent reticulocytes –> differentiates from regenerative anaemia >5-7 days

Question 2

what are the two mechanisms of NRA?

Answer 2

1. decreased erythropoiesis (not enough RBC)

2. defective erythropoiesis (defective RBC)

Question 3

what are the 5 causes of reduced erythropoiesis?

Answer 3

1. anaemia of inflam disease/ chronic disease
2. decreased EPO production
3. immune mediated destruction of precursors
4. marrow diseases that cause NRA
5. infections causing NRA

Question 4

what is the most common cause and mechanism of reduced erythropoiesis?

Answer 4

anaemia of inflam disease/ chronic disease

mechanisms: inhibition of EPO, iron sequestration, decrease RBC survival

Question 5

what are the laboratory find gins associated with anaemia of inflam disease?

Answer 5

normocytic, normochronic cells: normal size and colour.
mild to moderate anaemia - 20-30% HCt
decreased serum iron
evident of inflam and chronic disease eg/ tumour, renal disease

Question 6

what are some causes for decreased EPO production?

Answer 6

chronic renal disease - decrease EPO prod, Decrease RBC lifespan, promote GIT bleeding and ulceration = suppression of erythopoeisis

endocrine disease - hypoadrenocorticism, hypoadrogenism, hypopititarism

Question 7

how is immune mediated destruction of precursor different to IMHA?

Answer 7

complete RBC aplasia (no RBC precursor in marrow)
much less common
appears to be based on response to corticosteroids

Question 8

what are some marrow diseases that cause NRA?

Answer 8

myelophtisis - infiltration of neoplastic cells in marrow
myelofibrosis - fibrosis in marrow
myeloproliferative disease - primary neoplasm in the marrow
marrow toxicity/damage - braken fern

Question 9

what are some infectious causes of NRA?

Answer 9

FeLV - kill RBC stem cell and progenitor cells
anaplasma infection
parvovirus - kills rapidly dividing cells

Question 10

what are some causes of defective erythropoiesis?

Answer 10

lead poisoning
iron, copper, cobalt, folate, B6, B12 deficiencies
genetic disorders of erythropoiesis
metabolic disorders

Question 11

what is the most common cause of defective erythropoiesis and what are the hallmarks?

Answer 11

iron deficiency
most common reason for iron deficiency is external blood loss
hallmarks: microcytic, hypochromic
decreased iron = decreased hb synth allowing increasing division before RBC maturation = look for fragmentation

Question 12

what are some common causes of iron deficiency

Answer 12

chronic external blood low eg/ chronic GIT bleed
defective iron transport/metabolism/hepatic insufficiency
very rarely iron deficient diet.

Question 13

how does lead poisoning defect erythropoiesis

Answer 13

results in defective ahem synthesis

Question 14

what are the clinical signs of lead poisoning

Answer 14

GIT and nervous system signs –> not associated with anaemia

Question 15

what are the RBC findings with lead poisoning

Answer 15

inappropriate metarubricytosis and basophilic stippling

appropriate if its with reticulocytosis in regen

Question 16

what are some genetic disorders of erythrocytosis

Answer 16

microcytosis common in asian breeds

macrocytosis common in poodle breeds

Question 17

name two metabolic disorders causing defective erythropoiesis

Answer 17

PFK deficiency

PK deficiency9

Question 18

what is erythrocytosis/polycythaemia

Answer 18

increased RBC - Hct, PCV, RBCC, Hb

Question 19

what are the two types of erythrocytosis

Answer 19

1. relative

2. absolute

Question 20

what are the clinical signs of erythrocytosis

Answer 20

seizures, behavioural changes, red mucus membranes, thomboemolic disease

Question 21

what are the causes of relative erythrocytosis?

Answer 21

dehydration. decrease water content, plasma RBC rise

redistribution of RBC - splenic contraction

Question 22

what are the two cases of absolute erythocytosis

Answer 22

1. polycthaemia vera: bone marrow irregulated with tumour.
2. increased EPO - appropriate response to chronic hypoxia, eg/ chronic pulmonary disease, R–> L shunting of blood,
   inappropriate = renal lessons

or can be breed specific ie/ greyhounds have higher ref interval.

Question 23

how would you diagnostically approach erythocytosis?

Answer 23

physical exam - check hydration status 
check for persistent re-hydration
rule out cardiovasc disease
assess EPO levels 
imaging for renal lessons
bone marrow eval 
endocrine test